Representation of locality in a biological information system

Some 5,000 dorsal root axons innervate 100,000 hairs on the rabbit ear, and each hair is innervated by 4–6 axons. Assuming predetermined cause, it is shown that this biological information system transmits information specifying locality and force of stimulation in such a way that error is effectively controlled for minimal natural stimuli. Under conditions of maximal stimulation, however, absolute representation of locality of all stimulated hairs is not achieved. This limitation is probably of little importance for the animal and is compensated for by the large reduction in volume of transmission lines. The biological system is compared with von Neumann's theoretical model for the control of error in automata by multiplexing.     

Characteristics of Virulent, Attenuated, and Avirulent Mycoplasma pneumoniae Strains

Homologous pairs of virulent and attenuated or avirulent Mycoplasma pneumoniae strains were derived and compared in an effort to elucidate the mechanisms of virulence. These related strains were found to vary in growth, glycolysis, protein electrophoretic patterns, peroxide formation, morphology, and cytadsorption. Variations in the last two characteristics closely correlated with avirulence. This enables understanding of one stage in the pathogenic sequence and provides a convenient marker for avirulence. The derivation of infectious avirulent strains may make possible their use as live vaccines against M. pneumoniae disease.